Discusses HIV, a virus that attacks white blood cells called CD4+ cells which are an important part of the immune system. Covers symptoms and stages of infection, including last stage called AIDS (acquired immunodeficiency syndrome). Covers HIV treatment.

Discusses HIV, a virus that attacks white blood cells called CD4+ cells which are an important part of the immune system. Covers symptoms and stages of infection, including last stage called AIDS (acquired immunodeficiency syndrome). Covers HIV treatment.

HIV (Human Immunodeficiency Virus) Infection

Topic Overview

What is HIV? What is AIDS?

HIV (human
immunodeficiency virus) is a virus that attacks the
immune system, the body's natural defence system.
Without a strong immune system, the body has trouble fighting off disease. Both
the virus and the infection it causes are called HIV.

White blood cells are an important part of the immune system. HIV infects and
destroys certain white blood cells called CD4+ cells. If too many CD4+ cells
are destroyed, the body can no longer defend itself against infection.

The last stage of HIV infection is
AIDS (acquired immunodeficiency syndrome). People with
AIDS have a low number of CD4+ cells and get infections or cancers that rarely
occur in healthy people. These can be deadly.

But having HIV doesn't mean you have AIDS. Even without treatment, it takes a long time for HIV to
progress to AIDS—usually 10 to 12 years.

When HIV is diagnosed before it becomes
AIDS, medicines can slow or stop the damage to the immune system. If AIDS does develop, medicines can often help the immune system return to a healthier state.

With
treatment, many people with HIV are able to live long and active lives.

There are two types of
HIV:

HIV-1, which causes almost all the cases of
AIDS worldwide

HIV-2, which causes
an AIDS-like illness. HIV-2 infection is uncommon in North America.

What causes HIV?

HIV infection is caused by the
human immunodeficiency virus. You can get HIV from contact with infected blood,
semen, or vaginal fluids.

Most people get the virus by having
unprotected sex with someone who has HIV.

Another common way of
getting it is by sharing drug needles with someone who is infected with
HIV.

The virus can also be passed from a mother to her baby during
pregnancy, birth, or breast-feeding.

HIV doesn't survive well outside the body. So it can't
be spread by casual contact like kissing or sharing drinking glasses with an
infected person.

What are the symptoms?

HIV may not cause symptoms
early on. People who do have symptoms may mistake them for the
flu or
mono. Common early symptoms include:

Symptoms may appear from a few days to several weeks
after a person is first infected. The early symptoms usually go away within 2
to 3 weeks.

After the early symptoms go away, an infected person
may not have symptoms again for many years. After a certain
point, symptoms reappear and then remain. These symptoms usually
include:

Swollen lymph nodes.

Extreme
tiredness.

Weight loss.

Fever.

Night
sweats.

How is HIV diagnosed?

A doctor may suspect HIV if symptoms last and no
other cause can be found.

If you
have been exposed to HIV, your immune system will make antibodies to try to
destroy the virus. Doctors use tests to find these antibodies in urine, saliva, or blood.

If a test on urine or saliva shows that you are infected
with HIV, you will probably have a blood test to confirm the results.

Most doctors use two blood tests, called the ELISA and the Western blot. If the first ELISA is positive (meaning that HIV antibodies are found),
the blood sample is tested again. If the second test is positive, a Western blot will be done to be sure.

HIV antibodies usually show up in the blood within 3 months but can take as long as 6 months. If you think you have been
exposed to HIV but you test negative for it:

Get tested again. Tests at 6, 12, and 24 weeks can be done to be sure you
are not infected.

Meanwhile, take steps to prevent the spread of
the virus, in case you do have it.

You can get HIV testing in most
doctors' offices, public health units, hospitals, and HIV care clinics.

How is it treated?

The standard treatment for HIV
is a combination of medicines called antiretroviral therapy, or ART. Antiretroviral medicines slow the rate at which the virus multiplies.

Taking these medicines can reduce the amount of virus in your body and help you
stay healthy.

To
monitor the HIV infection and its effect on your immune system, a doctor will
regularly do two tests:

Viral load, which shows the amount of virus
in your blood

CD4+ cell count, which shows how well your immune system is
working

After you start treatment, it's important to take your medicines exactly
as directed by your doctor. When treatment doesn't work, it is often because
HIV has become
resistant to the medicine. This can happen if you
don't take your medicines correctly.

How can you prevent HIV?

HIV is often spread by people who don't know they have it. So it's always important to protect yourself and others by taking these steps:

Practice safer sex. Use a condom every time
you have sex (including oral sex) until you are sure that you and your partner aren't infected with HIV or other sexually transmitted infection (STI).

Don't have more than one sex partner at a
time. The safest sex is with one partner who has sex only with
you.

Talk to your partner before you have sex the first time. Find
out if he or she is at risk for HIV. Get tested together. Getting tested again at 6, 12, and 24 weeks after the first test can be done to be sure neither of you
is infected. Use condoms in the meantime.

Don't drink a lot of alcohol
or use illegal drugs before sex. You might let down your guard and not practice
safer sex.

Cause

The HIV infection is caused by the
human immunodeficiency virus (HIV).

After
HIV is in the body, it starts to destroy CD4+ cells, which are white blood cells that help the body fight infection and disease.

HIV is spread when blood,
semen, or vaginal fluids from an infected person enter
another person's body, usually through sexual contact, from sharing needles
when injecting drugs, or from mother to baby during birth.

Symptoms

HIV may not cause symptoms
early on. People who do have symptoms may mistake them for the
flu or
mono. Early symptoms of HIV are called acute retroviral syndrome. The symptoms may include:

These first symptoms can range from mild to severe and
usually disappear on their own after 2 to 3 weeks. But many people don't have symptoms or they have such mild symptoms that they don't notice them at this stage.

After the early symptoms go away, an infected person
may not have symptoms again for many years. After a certain
point, symptoms reappear and then remain.

Untreated HIV infection progresses in
stages. These stages are based on your symptoms and
the amount of the virus in your blood.

Is accidentally stuck with a needle or other sharp item
that is contaminated with HIV.

HIV may be spread more easily
in the early
stage of infection and again
later, when symptoms of HIV-related illness develop.

A woman who is infected
with HIV can spread the virus to her baby during pregnancy, delivery, or
breast-feeding.

How HIV is not spread

The virus doesn't survive well outside the body. So HIV cannot be spread through casual contact with an infected person, such as
by sharing drinking glasses, by casual kissing, or by coming into contact with the person's sweat or urine.

It is now extremely rare in Canada or the United States for HIV to
be transmitted by
blood transfusions or organ transplants.

The window period

After you've been infected, it can take 2 weeks to 6 months for your body to start making HIV antibodies.

This means that during this time you could have a negative HIV test, even though you have been infected and can spread the virus to others.

HIV without symptoms (asymptomatic). It may take years for HIV symptoms to develop. But even though no symptoms are present, the virus is multiplying (or making copies of itself) in the body during this time. HIV multiplies so quickly that the immune system cannot destroy the virus. After years of fighting HIV, the immune system starts to weaken.

AIDS, which occurs during the last stage of infection with HIV. If HIV goes untreated, AIDS develops in most people within 10 to 12 years after the initial infection. With treatment for HIV, the progression to AIDS may be delayed or prevented.

A small number of people who are infected with HIV are
rapid progressors. They develop AIDS within a few years if they don't get treatment. It is not known why the infection progresses faster in these
people.

Left
untreated, AIDS is often fatal within 18 to 24 months after it develops. Death
may occur sooner in people who
rapidly progress through the stages of HIV or in young
children.

Non-progressors and people who are HIV-resistant

A few people have
HIV that doesn't progress to more severe symptoms or disease. They are
referred to as
non-progressors.

A small number of people
never become infected with HIV despite years of exposure to the virus. These
people are said to be
HIV-resistant.

What Increases Your Risk

Sexual contact

You have an
increased risk of becoming infected with HIV through sexual contact if
you:

Have unprotected sex (do not use
condoms).

Have multiple sex partners.

Are a man who has
sex with other men.

Have high-risk partner(s) (partner has multiple
sex partners, is a man who has sex with other men, or injects
drugs).

Suspected or known exposure to HIV but no symptoms

You have engaged in high-risk behaviour and are concerned that
you were exposed to HIV.

Your sex partner engages in high-risk
behaviour.

Your sex partner may have been exposed to
HIV.

Your sex partner has HIV.

You have any of the
symptoms listed above.

Getting tested for HIV can be scary, but the condition
can be managed with treatment. So it is important to get tested if you think you have been
exposed.

Watchful waiting

If you don't have symptoms of HIV even though you have
tested positive for the virus, you and your doctor may simply keep watching
for symptoms to occur.

If you don't show any signs of disease and your CD4+
cell count is more than 500 cells per microlitre (mcL), you may not need
treatment. But during this time you still need regular checkups with a doctor
to monitor the amount of
HIV in your blood and see how well your immune system is working.

Examinations and Tests

Early detection

The
Public Health Agency of Canada says you should consider getting tested for HIV if you or your partner(s) has ever:

Had sex without using a condom or other protective barrier.

Had sex under the influence of alcohol or drugs (you may not have used protection).

Tested positive for another sexually transmitted or blood-borne infection, such as syphilis, gonorrhea, chlamydia, hepatitis B, or hepatitis C.

Shared needles, syringes or other drug use equipment when using drugs, including steroids.

Had tattooing, piercing, or acupuncture with unsterilized equipment.

You and your doctor can decide if testing is right for you.

Fear of being tested

Some people are afraid to be tested for HIV. But if there
is any chance you could be infected, it is very important to find out. HIV can
be treated. Getting early treatment can slow down the virus and help you stay
healthy. And you need to know if you are infected so you can prevent spreading
the infection to other people.

Your doctor may recommend counselling before and after HIV testing. It
is usually available at the hospital or clinic where you will be tested. This
will give you an opportunity to:

Discuss your fears about being
tested.

Learn how to reduce your risk of becoming infected if your
test is negative.

Learn how to keep from spreading HIV to others if
your test is positive.

Think about personal issues, such as how
having HIV will affect you socially, emotionally, professionally, and
financially.

Learn what you need to do to stay healthy as long as
possible.

Testing
positive for HIV will probably make you anxious and afraid about your future.
Denial, fear,
and
depression are common reactions.

Don't be afraid to ask for the emotional support you need. If your family and
friends aren't able to provide you with support, a
professional counsellor can help.

The good news is that people being treated for HIV are living longer than ever
before with the help of medicines that can often prevent AIDS from developing. Your doctor can help you understand
your condition and how best to treat it.

Blood tests for HIV

HIV is diagnosed when
antibodies to HIV are found in the blood. The two
main blood tests are:

HIV is diagnosed only after two or more positive ELISA tests are confirmed by one positive Western blot assay. These tests usually can be done on the same blood sample.

ELISA test results usually come back in 2 to 4 days.
Results of the Western blot take 1 to 2 weeks. Rapid antibody tests are available that give results right away. But positive results of the rapid test need to be confirmed by the ELISA or Western blot test.

You've been having treatment and your viral load numbers become detectable after not being detectable.

How is AIDS diagnosed?

AIDS is the
last and most severe stage of HIV infection. It is diagnosed if the results of
your test show that you have a certain kind of infection called an
opportunistic infection that is common in people who
have weakened immune systems, such as
Kaposi's sarcoma or Pneumocystispneumonia.

Treatment Overview

The most effective treatment for
HIV is
antiretroviral therapy (ART), a
combination of several medicines that aims to control the amount
of virus in your body. For more information, see Medications.

Other steps you can take include the following:

Keep your
immune system strong by eating right, quitting smoking, and learning how to avoid infection. For more information, see Home Treatment.

Monitor your
CD4+ (white blood cells) counts to check the effect of
the virus on your immune system. For more information, see Examinations and Tests.

See a counsellor to help you handle the strong emotions and stress that can follow an HIV diagnosis. For more information, see Other Treatment.

Reduce stress so that you can better manage the HIV illness. For more information, see Other Treatment.

Starting treatment

The Canadian AIDS Treatment Information Exchange (CATIE) recommends that, if possible, people begin antiretroviral therapy (ART) for HIV before their CD4+ count falls below 350 cells/mcL. Treatment is especially important for pregnant women, people who have other infections (such as tuberculosis or hepatitis), and people who have symptoms of AIDS.2
Talk with your doctor about when you should start ART.

Research suggests that
treatment of early HIV with antiretroviral medicines has long-term
benefits, such as a stronger immune system.1

But you may decide not to get treated at first. If you put off treatment, you will still need regular checkups to measure the amount of
HIV in your blood and check how well your immune system is working.

You may want to start HIV treatment if your sex partner doesn't have HIV. Treatment of your HIV infection can help prevent the spread of HIV to your sex partner.1

Treatment for AIDS

If
HIV progresses to a late stage,
treatment will be started or continued to keep your immune system as healthy as possible.

If you get any diseases that point to AIDS, such as Pneumocystis pneumonia or Kaposi's sarcoma, your doctor will treat them.

Many important end-of-life decisions can be made while
you are active and able to communicate your wishes. For more information, see
the topic
Care at the End of Life.

Treatment to prevent HIV infection

Health care workers
who are at risk for HIV because of an accidental needle stick or other
exposure to body fluids may need medicine to prevent infection.3

Medicine may also prevent HIV infection in a person who
has been raped or was accidentally exposed to the body fluids of a person who
may have HIV.4 This type of treatment is usually
started within 72 hours of the exposure.

Studies have shown that treatment with antiretroviral medicine also can reduce the risk of an uninfected person getting infected through sex.5, 6

Prevention

Safer sex

Practice safer sex. This includes using a
condom unless you are in a
relationship with one partner who does not have HIV or other sex
partners.

If you do have sex with someone who has HIV, it is
important to practice safer sex and to be regularly tested for
HIV.

Talk with your sex partner or partners about their sexual
history as well as your own sexual history. Find out whether your partner has a history of behaviours that increase his or her risk for HIV.

You may be able to take a combination medicine (tenofovir plus emtricitabine) every day to help prevent infection with HIV. This medicine can lower the risk of getting HIV.6, 7, 5 But you still need to practice safer sex to keep your risk low.

Alcohol and drugs

If you use alcohol or drugs, be very careful. Being under the influence can make you careless about practicing safer sex.

And never share
intravenous (IV) needles, syringes, cookers, cotton,
cocaine spoons, or eyedroppers with others if you use drugs.

If you already have HIV

If you are infected with HIV, you can greatly lower the risk of spreading the infection to your sex partner by starting treatment when your immune system is still healthy.

The Canadian AIDS Treatment Information Exchange (CATIE) recommends that, if possible, people begin antiretroviral therapy (ART) for HIV before their CD4+ count falls below 350 cells/mcL. Treatment is especially important for pregnant women, people who have other infections (such as tuberculosis or hepatitis), and people who have symptoms of AIDS.2
Talk with your doctor about when you should start ART.

A large study found that early treatment greatly lowers the risk of spreading HIV to an uninfected partner.8 This study was done mainly with heterosexual couples, so the effectiveness of HIV treatment in preventing the spread of HIV to a same-sex partner may be different.

Steps to avoid spreading HIV

If you are HIV-positive (infected with HIV) or have engaged
in sex or needle-sharing with someone who could be infected with HIV, take
precautions to avoid spreading the infection to others.

Tell your sex partner or partners about your
behaviour and whether you are HIV-positive.

Follow safer sex
practices, such as using condoms.

Do not donate blood, plasma,
semen, body organs, or body tissues.

Do
not share personal items, such as toothbrushes, razors, or sex toys, that may
be contaminated with blood, semen, or vaginal fluids.

If you are pregnant

The risk of a woman spreading HIV to her baby can be
greatly reduced if she:

Is on medicine that reduces the amount of virus in her blood to
undetectable levels during pregnancy.

Continues treatment during pregnancy.

Does not breast-feed her baby.

The baby should also receive
treatment after it is born.

Home Treatment

If you are infected with
HIV, you can lead an active life for a long time.

Don't smoke. People with HIV are more likely to have a
heart attack or get lung cancer.10, 11 Cigarette smoking can raise these
risks even more.

Don't use illegal drugs. And limit your use of alcohol.

Join a support group

Support groups are often good places to share information, problem-solving tips, and emotions related to HIV infection.

You may be able to find a support group by searching the Internet. Or you can ask your doctor to help you find one.

Prevent other illnesses

Get the
immunizations and the medicine treatment you need to prevent certain
infections or illnesses, such as some types of
pneumonia or cancer that are more likely to develop in
people who have a weakened immune system.

Tips for caregivers

A skilled caregiver can provide the
emotional, physical, and medical care that will improve the quality of life for
a person who has HIV.

How likely it is that the virus
will become
resistant to a certain type of medicine.

Medicine side effects and your willingness to live with
them.

Medicines for HIV may have unpleasant side effects. They may sometimes make you feel worse than you
did before you started taking them. Talk to your doctor about your side
effects. He or she may be able to adjust your medicines or prescribe a
different one.

You may be able to take several medicines combined
into one pill. This reduces the number of pills you have to take each
day.

Treatment failure

If your viral load doesn't
drop as expected, or if your CD4+ cell count starts to fall, your doctor will
try to find out why the treatment didn't work.

There are
two main reasons that treatment fails:

The virus that causes HIV has become
resistant. The medicine no longer works to control virus multiplication or
protect your immune system. Tests can show if resistance has
occurred. You may need a different combination of medicines.

You did not take your medicine as prescribed. If you have
trouble taking the medicines exactly as prescribed, talk with your
doctor.

Related Information

References

Citations

U.S. Department of Health and Human Services Panel on Antiretroviral Guidelines for Adults and Adolescents (2013). Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents. Available online: http://www.aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf.

Canadian AIDS Treatment Information Exchange (2011). A Practical Guide to HIV Drug Treatment for People Living with HIV. 3.4, When to Start. Available online: http://www.catie.ca/en/practical-guides/practical-guide-hiv-drug-treatment-people-living-hiv/3-treating-hiv/34-when-start.

Centers for Disease Control and Prevention (2005).
Updated U.S. Public Health Services guidelines for the management of
occupational exposures to HIV and recommendations for postexposure prophylaxis.
MMWR, 50(RR-09): 1–17. Available online:
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5409a1.htm.

Centers for Disease Control and Prevention (2005). Antiretroviral postexposure prophylaxis after sexual, injection-drug use, or other nonoccupational exposure to HIV in the United States. Recommendations from the U.S. Department of Health and Human Services. Available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5402a1.htm.

Grant RM, et al. (2010). Preexposure chemoprophylaxis for HIV prevention
in men who have sex with men. New England Journal of Medicine, 363(27): 2588–2599.

U.S. Centers for Disease Control and Prevention (2011). Interim guidance: Preexposure prophylaxis for the prevention of HIV infection in men who have sex with men. MMWR, 60(03): 65–68. Also available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6003a1.htm.

U.S. Centers for Disease Control and Prevention (2011). CDC trial and another major study find PrEP can reduce risk of HIV infection among heterosexuals. Available online: http://www.cdc.gov/nchhstp/newsroom/PrEPHeterosexuals.html.

Panel on Opportunistic Infections in HIV-Exposed and HIV-Infected Children (2013). Guidelines for the prevention and treatment of opportunistic infections in HIV-exposed and HIV-infected children. Rockville, MD: Department of Health and Human Services. http://aidsinfo.nih.gov/contentfiles/lvguidelines/oi_guidelines_pediatrics.pdf. Accessed April 16, 2014.

U.S. Centers for Disease Control and Prevention (2009). Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: Recommendations from CDC, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America. MMWR, 58(Early Release): 1–207.

World Health Organization (2010). Antiretroviral therapy for HIV infection in adults and adolescents: Recommendations for a public health approach. Available online: http://whqlibdoc.who.int/publications/2010/9789241599764_eng.pdf.

World Health Organization (2010). Guidelines on HIV and infant feeding 2010: Principles and recommendations
for infant feeding in
the context of HIV
and a summary
of evidence. Available online: http://whqlibdoc.who.int/publications/2010/9789241599535_eng.pdf.

U.S. Department of Health and Human Services Panel on Antiretroviral Guidelines for Adults and Adolescents (2013). Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents. Available online: http://www.aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf.

Canadian AIDS Treatment Information Exchange (2011). A Practical Guide to HIV Drug Treatment for People Living with HIV. 3.4, When to Start. Available online: http://www.catie.ca/en/practical-guides/practical-guide-hiv-drug-treatment-people-living-hiv/3-treating-hiv/34-when-start.

Centers for Disease Control and Prevention (2005).
Updated U.S. Public Health Services guidelines for the management of
occupational exposures to HIV and recommendations for postexposure prophylaxis.
MMWR, 50(RR-09): 1–17. Available online:
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5409a1.htm.

Centers for Disease Control and Prevention (2005). Antiretroviral postexposure prophylaxis after sexual, injection-drug use, or other nonoccupational exposure to HIV in the United States. Recommendations from the U.S. Department of Health and Human Services. Available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5402a1.htm.

Grant RM, et al. (2010). Preexposure chemoprophylaxis for HIV prevention
in men who have sex with men. New England Journal of Medicine, 363(27): 2588–2599.

U.S. Centers for Disease Control and Prevention (2011). Interim guidance: Preexposure prophylaxis for the prevention of HIV infection in men who have sex with men. MMWR, 60(03): 65–68. Also available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6003a1.htm.

U.S. Centers for Disease Control and Prevention (2011). CDC trial and another major study find PrEP can reduce risk of HIV infection among heterosexuals. Available online: http://www.cdc.gov/nchhstp/newsroom/PrEPHeterosexuals.html.

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